1. Field of This Invention
Ths invention relates to a device for collecting cell material from body cavities, which composes a guide tube and a cell sampler which is retractable into the guide tube. In particular, this invention relates to an instrument for collecting cell material from the endometrium.
2. Prior Art
Examination of the endometrium is important for the diagnosis of premalignant and malignant tissue changes. It is also advisable, however, for case control after taking therapeutic measures, and for the functional diagnosis of the endometrium, which includes the assessment of hormonally induced effects or change due to pregnancy.
The examination of single cells is highly significant for clinical diagnosis, in particular for the early recognition of cancers. It is based on the principle of exfoliative cytology, i.e., on the examination of tumor cells which are spontaneously exfoliated from the cancer tissue or can be easily made to exfoliate. These cells must be easy to judge and clearly distinguishable from normal cells.
The problems of cell diagnosis on the endometrium are due to the fact, for example, that hormonally controlled proliferating processes may induce cell changes in the endometrium which make the detection of possibly existing atypical cells difficult. An additional problem is due to the difficulties in collecting endometrial cells, which in principle can be avoided only by an improved sampling technique.
In general, the endometrium is collected by means utilizing abrasion. For the evaluation of mucosal relief radiographs, on the other hand, collection of a tissue strip is sufficient. These methods involve surgery. However, numerous other methods for the collection of cells have been developed which need not be carried out under anesthesia. It should be noted, however, that all these collection methods and instruments require great skill and involve drawbacks which are essentially due to their mode of operation.
In the case of the conventional aspiration and irrigation methods (e.g., the Pistolet method or the Gravlee Jet-Wash method), the method of the material removed by aspiration or irrigation depends on the degree of exfoliation of the endometrium. Only such cells can be collected which lie on the surface of the endometrium in loose formations. The effect of the rinsing pressure on the tissue in the uterine lumen is non-uniform and uncontrollable. In addition, the cells cannot be collected from all regions, and the cells collected usually are in a poor state of conservation.
Swabbing with brush-type instruments (e.g., the Medhosa cannula and the device described in U.S. Pat. No. 3,881,464) does not involve significant advantages either, as the effect of such devices on the uterine mucosa cannot be controlled and the cell yield and the prevention of injuries depend on the skill of the operator. In addition, removal of the cells is difficult, as pieces of the mucosa remain trapped in the bristles of the devices.
Other swab cannulas (e.g., the Milan-Markey spiral) have a very harsh effect on the endometrium so that lesions or hemorrhages may result. Such instruments also do not permit controlled application and do not guarantee representative cell collection.